<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>My WebSocket</title>
    <style>
        #message{
            margin-top:40px;
            border:1px solid gray;
            padding:20px;
            height: 500px;
            /*自动换行防止溢出*/
            word-break:break-all;
            /*padding:5px;*/
            /*将超出对象高度的内容进行裁剪，并以滚动条的方式显示超出的内容。*/
            overflow-y:scroll;
            /*解决内容溢出问题
            overflow:hidden*/
        }
    </style>
</head>
<body>
<input onclick="conectWebSocket()" value="连接Web聊天室" type="button">
<input onclick="closeWebSocket()" value="断开连接" type="button">
<hr />
<br />
消息：<input id="text" type="text" />
<input type="button" onclick="send()" value="发送消息">
<div id="message"></div>
</body>
<script type="text/javascript">
    var websocket = null;
    function conectWebSocket(){
        //判断当前浏览器是否支持WebSocket
        if ('WebSocket'in window) {
            websocket = new WebSocket("ws://localhost:8080/webSocket");
        } else {
            alert('Not support websocket')
        }
        //连接发生错误的回调方法
        websocket.onerror = function() {
            setMessageInnerHTML("error");
        };
        //连接成功建立的回调方法
        websocket.onopen = function(event) {
            setMessageInnerHTML("ChuZhong聊天室: 成功建立连接");
        }
        //接收到消息的回调方法
        websocket.onmessage = function(event) {
            setMessageInnerHTML(event.data);
        }
        //连接关闭的回调方法
        websocket.onclose = function() {
            setMessageInnerHTML("ChuZhong聊天室:关闭连接");
        }
        //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
        window.onbeforeunload = function() {
            websocket.close();
        }
    }
    //将消息显示在网页上
    function setMessageInnerHTML(innerHTML) {
        var messageDiv = document.getElementById("message");
        // 通过js显示底部信息
        messageDiv.scrollTop = messageDiv.scrollHeight;
        document.getElementById('message').innerHTML += innerHTML + '<br/>';
    }
    //关闭连接
    function closeWebSocket() {
        websocket.close();
    }
    //发送消息
    function send() {
        var message = document.getElementById('text').value;
        websocket.send(message);
    }
</script>
</html>
